Machine does not enter/stay in Standby (XP)

My new thinkpad running on Windows XP Pro has problem entering standby. If I press Fn+F4 to go standby, first there is a short beep, screen goes off, and the moon-shaped standby indicator is lighted; HOWEVER, within 5 seconds (sometimes 1 min), there is another beep, and the moon-shaped standby indicator is off (not lighted any more), and all the other indicators (HDD, Cap and Number indicators) flash a few times as if something going on, then everything calms down, with only the AC and power indicators on (standby indicator remains off). But it is not in standby but in locked state, because pressing any key (not necessarily the Fn key) will turn on the screen, which says "this computer is in use and has been locked...".

This happens maybe more than 90% of times I want it go standby. Also the automatically scheduled standby (say 10 min) often doesn't work: after half hour or more, the system is still on.

I searched the topic and some people identified various .dll files, but I didn't find those files on my machine. I ran hijackthis and got this log:

-------------------------begin log file------------------------------------

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 12:51:52 PM, on 9/26/2009
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16876)
Boot mode: Normal

Running processes:
C:\WINDOWS\System32\smss.exe
C:\WINDOWS\system32\winlogon.exe
C:\WINDOWS\system32\services.exe
C:\WINDOWS\system32\lsass.exe
C:\WINDOWS\system32\ibmpmsvc.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\Program Files\Intel\Wireless\Bin\S24EvMon.exe
C:\WINDOWS\system32\spoolsv.exe
C:\WINDOWS\system32\IPSSVC.EXE
C:\Program Files\ThinkPad\ConnectUtilities\AcPrfMgrSvc.exe
C:\PROGRA~1\AVG\AVG8\avgwdsvc.exe
C:\Program Files\Diskeeper Corporation\Diskeeper\DkService.exe
C:\Program Files\Intel\Wireless\Bin\EvtEng.exe
C:\PROGRA~1\AVG\AVG8\avgrsx.exe
C:\PROGRA~1\AVG\AVG8\avgnsx.exe
C:\Program Files\Intel\Wireless\Bin\RegSrvc.exe
C:\Program Files\Microsoft\Search Enhancement Pack\SeaPort\SeaPort.exe
C:\WINDOWS\system32\svchost.exe
c:\program files\lenovo\system update\suservice.exe
C:\Program Files\Common Files\Lenovo\tvt_reg_monitor_svc.exe
C:\WINDOWS\System32\TPHDEXLG.exe
C:\Program Files\Lenovo\Rescue and Recovery\rrpservice.exe
C:\Program Files\Lenovo\Rescue and Recovery\rrservice.exe
c:\Program Files\Common Files\Lenovo\Scheduler\tvtsched.exe
C:\Program Files\Lenovo\Rescue and Recovery\ADM\IUService.exe
C:\PROGRA~1\AVG\AVG8\avgemc.exe
C:\Program Files\Common Files\Lenovo\Logger\logmon.exe
C:\Program Files\ThinkPad\ConnectUtilities\AcSvc.exe
C:\Program Files\AVG\AVG8\avgcsrvx.exe
C:\Program Files\ThinkPad\ConnectUtilities\SvcGuiHlpr.exe
C:\WINDOWS\system32\rundll32.exe
C:\Program Files\Lenovo\NPDIRECT\TPFNF7SP.exe
C:\WINDOWS\system32\tp4serv.exe
C:\Program Files\Lenovo\HOTKEY\TPOSDSVC.exe
C:\WINDOWS\system32\TpShocks.exe
C:\PROGRA~1\ThinkPad\UTILIT~1\EzEjMnAp.Exe
C:\Program Files\Analog Devices\Core\smax4pnp.exe
C:\WINDOWS\system32\igfxtray.exe
C:\WINDOWS\system32\hkcmd.exe
C:\Program Files\Lenovo\HOTKEY\TPONSCR.exe
C:\Program Files\Lenovo\Zoom\TpScrex.exe
C:\WINDOWS\system32\igfxpers.exe
C:\WINDOWS\system32\igfxsrvc.exe
C:\Program Files\Java\jre1.5.0_06\bin\jusched.exe
C:\Program Files\Diskeeper Corporation\Diskeeper\DkIcon.exe
C:\PROGRA~1\THINKV~2\PrdCtr\LPMGR.exe
C:\Program Files\ThinkVantage\AMSG\Amsg.exe
C:\Program Files\ThinkPad\ConnectUtilities\ACTray.exe
C:\Program Files\ThinkPad\ConnectUtilities\ACWLIcon.exe
C:\Program Files\Logitech\MouseWare\system\em_exec.exe
C:\PROGRA~1\AVG\AVG8\avgtray.exe
C:\Program Files\Common Files\Lenovo\Scheduler\scheduler_proxy.exe
C:\WINDOWS\system32\ctfmon.exe
C:\WINDOWS\system32\wuauclt.exe
C:\WINDOWS\system32\ntvdm.exe
C:\WINDOWS\explorer.exe
C:\Program Files\Mozilla Firefox\firefox.exe
C:\Program Files\AVG\AVG8\avgui.exe
C:\Program Files\AVG\AVG8\avgscanx.exe
C:\Program Files\AVG\AVG8\avgcsrvx.exe
C:\Program Files\Trend Micro\HijackThis\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://lenovo.live.com
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://lenovo.live.com
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://go.microsoft.com/fwlink/?LinkId=54896
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://go.microsoft.com/fwlink/?LinkId=54896
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://go.microsoft.com/fwlink/?LinkId=69157
O2 - BHO: AcroIEHelperStub - {18DF081C-E8AD-4283-A596-FA578C2EBDC3} - C:\Program Files\Common Files\Adobe\Acrobat\ActiveX\AcroIEHelperShim.dll
O2 - BHO: RealPlayer Download and Record Plugin for Internet Explorer - {3049C3E9-B461-4BC5-8870-4C09146192CA} - C:\Program Files\Real\RealPlayer\rpbrowserrecordplugin.dll
O2 - BHO: WormRadar.com IESiteBlocker.NavFilter - {3CA2F312-6F6E-4B53-A66E-4E65E497C8C0} - C:\Program Files\AVG\AVG8\avgssie.dll
O2 - BHO: (no name) - {5C255C8A-E604-49b4-9D64-90988571CECB} - (no file)
O2 - BHO: Search Helper - {6EBF7485-159F-4bff-A14F-B9E3AAC4465B} - C:\Program Files\Microsoft\Search Enhancement Pack\Search Helper\SEPsearchhelperie.dll
O2 - BHO: SSVHelper Class - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre1.5.0_06\bin\ssv.dll
O2 - BHO: Windows Live Sign-in Helper - {9030D464-4C02-4ABF-8ECC-5164760863C6} - C:\Program Files\Common Files\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O2 - BHO: Windows Live Toolbar Helper - {E15A8DC0-8516-42A1-81EA-DC94EC1ACF10} - C:\Program Files\Windows Live\Toolbar\wltcore.dll
O2 - BHO: ThinkVantage Password Manager - {F040E541-A427-4CF7-85D8-75E3E0F476C5} - C:\Program Files\Lenovo\Client Security Solution\tvtpwm_ie_com.dll
O3 - Toolbar: &Windows Live Toolbar - {21FA44EF-376D-4D53-9B0F-8A89D3229068} - C:\Program Files\Windows Live\Toolbar\wltcore.dll
O3 - Toolbar: Easy-WebPrint - {327C2873-E90D-4c37-AA9D-10AC9BABA46C} - C:\Program Files\Canon\Easy-WebPrint\Toolband.dll
O4 - HKLM\..\Run: [PWRMGRTR] rundll32 C:\PROGRA~1\ThinkPad\UTILIT~1\PWRMGRTR.DLL,PwrMgrBkGndMonitor
O4 - HKLM\..\Run: [BLOG] rundll32 C:\PROGRA~1\ThinkPad\UTILIT~1\BatLogEx.DLL,StartBattLog
O4 - HKLM\..\Run: [TPFNF7] C:\Program Files\Lenovo\NPDIRECT\TPFNF7SP.exe /r
O4 - HKLM\..\Run: [TrackPointSrv] tp4serv.exe
O4 - HKLM\..\Run: [TPHOTKEY] C:\Program Files\Lenovo\HOTKEY\TPOSDSVC.exe
O4 - HKLM\..\Run: [TpShocks] TpShocks.exe
O4 - HKLM\..\Run: [EZEJMNAP] C:\PROGRA~1\ThinkPad\UTILIT~1\EzEjMnAp.Exe
O4 - HKLM\..\Run: [SoundMAXPnP] C:\Program Files\Analog Devices\Core\smax4pnp.exe
O4 - HKLM\..\Run: [SoundMAX] C:\Program Files\Analog Devices\SoundMAX\Smax4.exe /tray
O4 - HKLM\..\Run: [IgfxTray] C:\WINDOWS\system32\igfxtray.exe
O4 - HKLM\..\Run: [HotKeysCmds] C:\WINDOWS\system32\hkcmd.exe
O4 - HKLM\..\Run: [Persistence] C:\WINDOWS\system32\igfxpers.exe
O4 - HKLM\..\Run: [SunJavaUpdateSched] C:\Program Files\Java\jre1.5.0_06\bin\jusched.exe
O4 - HKLM\..\Run: [LPManager] C:\PROGRA~1\THINKV~2\PrdCtr\LPMGR.exe
O4 - HKLM\..\Run: [AMSG] C:\Program Files\ThinkVantage\AMSG\Amsg.exe /startup
O4 - HKLM\..\Run: [ACTray] C:\Program Files\ThinkPad\ConnectUtilities\ACTray.exe
O4 - HKLM\..\Run: [ACWLIcon] C:\Program Files\ThinkPad\ConnectUtilities\ACWLIcon.exe
O4 - HKLM\..\Run: [Logitech Utility] Logi_MwX.Exe
O4 - HKLM\..\Run: [AVG8_TRAY] C:\PROGRA~1\AVG\AVG8\avgtray.exe
O4 - HKLM\..\Run: [TVT Scheduler Proxy] C:\Program Files\Common Files\Lenovo\Scheduler\scheduler_proxy.exe
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O8 - Extra context menu item: Easy-WebPrint Add To Print List - res://C:\Program Files\Canon\Easy-WebPrint\Resource.dll/RC_AddToList.html
O8 - Extra context menu item: Easy-WebPrint High Speed Print - res://C:\Program Files\Canon\Easy-WebPrint\Resource.dll/RC_HSPrint.html
O8 - Extra context menu item: Easy-WebPrint Preview - res://C:\Program Files\Canon\Easy-WebPrint\Resource.dll/RC_Preview.html
O8 - Extra context menu item: Easy-WebPrint Print - res://C:\Program Files\Canon\Easy-WebPrint\Resource.dll/RC_Print.html
O9 - Extra button: (no name) - {0045D4BC-5189-4b67-969C-83BB1906C421} - C:\Program Files\Lenovo\Client Security Solution\tvtpwm_ie_com.dll
O9 - Extra 'Tools' menuitem: ThinkVantage Password Manager... - {0045D4BC-5189-4b67-969C-83BB1906C421} - C:\Program Files\Lenovo\Client Security Solution\tvtpwm_ie_com.dll
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.5.0_06\bin\ssv.dll
O9 - Extra 'Tools' menuitem: Sun Java Console - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.5.0_06\bin\ssv.dll
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O18 - Protocol: linkscanner - {F274614C-63F8-47D5-A4D1-FBDDE494F8D1} - C:\Program Files\AVG\AVG8\avgpp.dll
O20 - Winlogon Notify: ACNotify - ACNotify.dll (file missing)
O20 - Winlogon Notify: avgrsstarter - C:\WINDOWS\SYSTEM32\avgrsstx.dll
O23 - Service: Ac Profile Manager Service (AcPrfMgrSvc) - Lenovo - C:\Program Files\ThinkPad\ConnectUtilities\AcPrfMgrSvc.exe
O23 - Service: Access Connections Main Service (AcSvc) - Lenovo - C:\Program Files\ThinkPad\ConnectUtilities\AcSvc.exe
O23 - Service: AVG Free8 E-mail Scanner (avg8emc) - AVG Technologies CZ, s.r.o. - C:\PROGRA~1\AVG\AVG8\avgemc.exe
O23 - Service: AVG Free8 WatchDog (avg8wd) - AVG Technologies CZ, s.r.o. - C:\PROGRA~1\AVG\AVG8\avgwdsvc.exe
O23 - Service: Diskeeper - Diskeeper Corporation - C:\Program Files\Diskeeper Corporation\Diskeeper\DkService.exe
O23 - Service: Intel(R) PROSet/Wireless Event Log (EvtEng) - Intel Corporation - C:\Program Files\Intel\Wireless\Bin\EvtEng.exe
O23 - Service: Google Update Service (gupdate) (gupdate) - Google Inc. - C:\Program Files\Google\Update\GoogleUpdate.exe
O23 - Service: Google Updater Service (gusvc) - Google - C:\Program Files\Google\Common\Google Updater\GoogleUpdaterService.exe
O23 - Service: ThinkPad PM Service (IBMPMSVC) - Lenovo - C:\WINDOWS\system32\ibmpmsvc.exe
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Common Files\InstallShield\Driver\1150\Intel 32\IDriverT.exe
O23 - Service: IPS Core Service (IPSSVC) - Lenovo Group Limited - C:\WINDOWS\system32\IPSSVC.EXE
O23 - Service: Intel(R) PROSet/Wireless Registry Service (RegSrvc) - Intel Corporation - C:\Program Files\Intel\Wireless\Bin\RegSrvc.exe
O23 - Service: Intel(R) PROSet/Wireless Service (S24EventMonitor) - Intel Corporation - C:\Program Files\Intel\Wireless\Bin\S24EvMon.exe
O23 - Service: System Update (SUService) - Lenovo Group Limited - c:\program files\lenovo\system update\suservice.exe
O23 - Service: ThinkVantage Registry Monitor Service - Lenovo Group Limited - C:\Program Files\Common Files\Lenovo\tvt_reg_monitor_svc.exe
O23 - Service: ThinkPad HDD APS Logging Service (TPHDEXLGSVC) - Lenovo. - C:\WINDOWS\System32\TPHDEXLG.exe
O23 - Service: TSS Core Service (TSSCoreService) - IBM - C:\Program Files\Lenovo\Client Security Solution\tvttcsd.exe
O23 - Service: TVT Backup Protection Service - Unknown owner - C:\Program Files\Lenovo\Rescue and Recovery\rrpservice.exe
O23 - Service: TVT Backup Service - Lenovo Group Limited - C:\Program Files\Lenovo\Rescue and Recovery\rrservice.exe
O23 - Service: TVT Scheduler - Lenovo Group Limited - c:\Program Files\Common Files\Lenovo\Scheduler\tvtsched.exe
O23 - Service: tvtnetwk - Unknown owner - C:\Program Files\Lenovo\Rescue and Recovery\ADM\IUService.exe

--
End of file - 10663 bytes
-------------------------------end of log file--------------------------------

If someone could find the cause or the file at issue for me to delete, I'll be really grateful!